• What is Western Disturbance:
  • It is an extra tropical storm that originates in the Mediterranean region and brings heavy winter rains to the Indian subcontinent’s northwestern regions.
  • The westerlies drive a non-monsoonal precipitation pattern.
  • Extratropical storms are a global phenomena that carry moisture in the high atmosphere, as opposed to their tropical counterparts, which carry moisture in the lower atmosphere.
  • When a storm system hits the Himalayas, moisture is sometimes released as rain on the Indian subcontinent.
  • How Western Disturbances are caused:
  • Western Disturbance is caused by extratropical cyclones that form in the Mediterranean Sea.
  • A high-pressure area forms over Ukraine and the surrounding region, allowing frigid air from the Polar Regions to enter an area of somewhat warmer air with significant moisture.
  • This encourages the formation of an eastward-moving extratropical depression by creating favourable circumstances for cyclogenesis in the upper atmosphere.
  • They make their way across the Middle East, passing via Iran, Afghanistan, and Pakistan on their way to the Indian subcontinent.
  • Impact:
  • Plays a key role in bringing moderate to heavy rain to low-lying portions of the Indian Subcontinent, as well as heavy snow to mountainous areas.
  • Cloudy skies, warmer night-time temperatures, and unexpected rain are frequently linked with this disturbance.
  • This precipitation is critical in agriculture, particularly for Rabi crops.
  • Wheat is one of the most significant crops that contributes to India’s food security.
  • Crop damage, landslides, floods, and avalanches can all be caused by excessive precipitation caused by this disturbance.
  • It brings cold waves and dense fog to the Indo-Gangetic plains on occasion.
  • Until another western disturbance disrupts the situation, these circumstances will remain stable.
  • A transient advancement of monsoon current develops across the region when western disturbances sweep across northwest India before to the onset of monsoon.
  • Source The Hindu

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